JP2005159000A - Semiconductor laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor laser which can detect outgoing power suitably in a semiconductor laser which offers a fixed optical path by using a grating and a mirror. <P>SOLUTION: The grating 3 performs light receiving of laser light from a laser diode 1 through a lens 2, emits primary diffracted light to the laser diode 1 and emits 0th light to the mirror 4. The 0th light is reflected with the mirror 4 and made to enter a beam splitter 5. Spectrum of the incident light is performed into transmitting light and reflected light. The reflected light is made to enter a detector 6, and outgoing power is detected. The grating 3 and the mirror 4 are rotated by using an axis of rotation 7 as a center, and wavelength of laser light emitted from the laser diode 1 is adjusted. Optical path of the transmitting light and the reflected light offered from the beam splitter 5 is not changed by the above rotation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an external resonator type semiconductor laser, and more particularly to a semiconductor laser capable of appropriately controlling an emission power.

  In recent years, semiconductor lasers have been widely used in information equipment because of their small size and low power consumption. Among these semiconductor lasers, there is an external resonator type semiconductor laser that stabilizes the wavelength of oscillation light of a semiconductor laser by entering light of a predetermined wavelength from the outside.

  Here, a typical Littrow type semiconductor laser will be described with reference to FIG. 5A. For example, longitudinal multimode laser light (oscillation light) emitted from a semiconductor laser element such as the laser diode 100 is collected in parallel by a lens 101 and is incident on a grating (diffraction grating) 102. The grating 102 reflects light having a specific wavelength among incident light as first-order diffracted light according to the arrangement angle. This first-order diffracted light is back-injected into the laser diode 100 via the lens 101. As a result, the laser diode 100 resonates with the injected first-order diffracted light and emits single-mode light, and the wavelength of the light is the same as the wavelength of the light returned from the grating 102.

  On the other hand, when using such a semiconductor laser, it is usually necessary to control the emission power of the semiconductor laser. However, since the relationship between the drive current and the emission power changes depending on the temperature or the like, the semiconductor laser manages the drive current. The output power cannot be controlled only with As one method for controlling the output power to a predetermined value, the output power of the light actually emitted from the semiconductor laser is detected by a detector (light detector) or the like, and the drive current of the semiconductor laser is determined based on the detected power. There is a method for feedback control.

  However, in the case of a Littrow type semiconductor laser or the like, when a constant wavelength is used or when a plurality of wavelengths are used, it is necessary to adjust the grating arrangement angle as described above. The position of the detector must be adjusted according to the angle. This situation will be described in detail with reference to FIG. 5B.

  Assume that the laser diode 100 shown in FIG. 5B is required to emit light of a certain wavelength. In the initial state, the oscillation light from the laser diode 100 enters the grating 102A through the lens 101, as in FIG. 5A. In FIG. 5B, two types of arrangements for grading are shown, and the gratings in the respective arrangement states are referred to using the corresponding reference numerals 102A and 102B. Further, when the grading itself is generally named regardless of the arrangement state, it is referred to using a reference numeral such as 102. In the subsequent drawings, a plurality of arrangement states may be shown for one grating, but the same reference is made to these. References other than grading are made in the same manner.

  When receiving the oscillation light from the laser diode 100, the grating 102A emits first-order diffracted light 103 and zero-order light 106A. The first-order diffracted light 103 is incident on the laser diode 100 and causes the laser diode 100 to emit single-mode light. The zero-order light 106A is received by the detector 104A, and the light amount of the zero-order light 106A is detected there.

  Here, when the wavelength has changed due to a change in ambient temperature or the like, as described above, the grating 102A is changed to the arrangement angle of the grating 102B, and control is performed to emit laser light having the original wavelength. . This is performed, for example, by rotating the grating 102 in the direction of the arrow a around the rotation axis 105 extending parallel to the extending direction of the grating grooves of the grating 102 on the surface of the grating 102. Then, the 1st-order diffracted light 103 reaches the laser diode 100 as in the previous state (however, the wavelength is changed), but the 0th-order light 106B enters the detector 104B with a shift by the rotation.

  As can be seen, this zero-order light 106B can no longer be detected by the detector 104A. Therefore, in such a case, it is necessary to prepare detectors arranged at different positions for each wavelength.

  Here, if the 0th-order beams 106A and 106B are incident on the same position, it is not necessary to prepare a detector for each wavelength, and the configuration of the semiconductor laser can be simplified. Techniques for solving such problems are known, and will be described with reference to FIGS. 6 to 8 (see Non-Patent Document 1).

T.M.Hard: "Laser Wavelength Selection and Output Coupling by a Grating", APPLIED OPTICS, Vol. 9, No. 8, August 1970, pp1825-1830

  FIG. 6 shows a configuration of a semiconductor laser in which laser light (oscillation light) from the laser diode 120 is incident on the grating 122 and the additional mirror 123. One end of the grating 122 is connected to one end of the mirror 123 at a predetermined angle, and the grating 122 and the mirror 123 rotate around the rotation shaft 124 while maintaining the predetermined angle. The rotating shaft 124 is provided at the other end of the grating 122 and extends perpendicular to the optical axis of the laser light from the laser diode 120 and parallel to the extending direction of the grating grooves of the grating.

  When the grating 122 and the mirror 123 are at the positions of the grating 122A and the mirror 123A, respectively, the grating 122A receives the laser light from the laser diode 120 and reversely injected into the laser diode 120, and the mirror 123A. 0th-order light 125A toward The 0th-order light 125A is reflected by the mirror 123A, and the reflected light 126A is emitted.

  Here, when the grating 122A and the mirror 123A are rotated about the rotation axis 124 in the direction of the arrow b, the grating 122A moves to the position of the grating 122B and the mirror 123A moves to the position of the mirror 123B. In response to this, the wavelength of the first-order diffracted light incident on the laser diode 120 changes. Further, the 0th-order diffracted light 125B is emitted, reflected by the mirror 123B, and the reflected light 126B is output.

  As described above, the reflected light 126A and the reflected light 126B output before and after changing the arrangement angle of the grating 122 become light in different directions. Therefore, in order to detect the emission power of these lights, each is suitable. It is necessary to place detectors at different positions. Therefore, it can be seen that the configuration shown in FIG. 6 has the problem described in relation to FIG. 5B.

  Next, how the light is reflected when the grating and the mirror move according to a predetermined rule when the zero-order light from the grating is received by the mirror will be described with reference to FIG. Here, one end of the grating 144 and one end of the mirror 145 are connected by a rotating shaft 150 that is horizontal in the extending direction of the grating grooves of the grating. The rotation shaft 150 is also the center of the circle 149. The angle formed by the surface of the grating and the surface of the mirror is V.

  Here, when a predetermined incident light 141 is given from point c to point d, the incident light 141 is incident on the grating 144 at the point d, and the zero-order light 142 is reflected at the same angle as the incident angle, and is reflected at the point e. move on. Therefore, the mirror 145 receives the 0th-order light 142 and emits the reflected light 143 toward the point f. A line obtained by extending the incident light 141 and a line obtained by extending the reflected light 143 intersect at a point j. These extended lines and the 0th-order light 142 line are tangents to the circle 149, respectively.

  Further, here, when the grating and the mirror are rotated around the rotation axis 150 while maintaining the angle V, they move to the positions of the grating 146 and the mirror 147 indicated by dotted lines, respectively. At this time, the predetermined incident light 141 extends from the point c to the point g, enters the grating 146 at the point g, and the zero-order light 148 is emitted. Zero-order light 148 extends from point g to point h, where it is reflected by mirror 147, and reflected light 143 extends from point h to point f.

  Even after the grating and the mirror are rotated, the line extending the incident light 141, the line extending the reflected light 143, and the line of the zero-order light 148 are tangent to the circle 149, respectively. From this, it can be seen that the angle formed by the predetermined incident light 141 and the reflected light 143 is maintained at a constant value of W if the grating and mirror are rotated under the conditions shown in the figure.

  If this principle is applied, even if the arrangement angle of the grating is changed, the reflected light of the laser diode can be emitted to a certain position, and as a result, the emission power of the light can be detected by one detector Can be configured. Next, an example of such a semiconductor laser will be described with reference to FIG.

  In the semiconductor laser of FIG. 8, for example, a grating 162A and a mirror 163A are arranged as shown in the figure in order to provide light of a certain wavelength. When the laser light from the laser diode 160 is provided to the grating 162A via the lens 161, the first-order diffracted light is back-injected into the laser diode 160, and at the same time, the zero-order light 165A is output to the mirror 163A. The mirror 163A reflects the received zero-order light 165A and emits reflected light 166A.

  Here, for example, when the wavelength of the laser light from the laser diode 160 changes due to a change in the ambient temperature or the like, the grating 162 and the mirror 163 are respectively replaced with the grating 162B and the mirror 163B in order to restore the wavelength. Change to the arrangement of. This is realized by rotating the grating 162A and the mirror 163A around the rotation axis 164 in the direction of the arrow c while maintaining the angle (positional relationship) between the grating 162A and the mirror 163A. As a result, the reflected light 166B is emitted from the mirror 163B.

  In this example, in order to keep the wavelength of the laser light from the laser diode 160 constant, the arrangement angle of the grating is changed. However, as shown in FIG. Since the grating and the mirror are rotated in this manner, the reflected light 166A, 166B takes the same optical path before and after the rotation.

  However, none of the above-described semiconductor lasers that provide a constant optical path using a grating and an additional mirror propose an advantageous structure for detecting the output power. In addition, a semiconductor laser configured to detect the output power using only the transmission type grating without using an additional mirror, or configured to detect the output power using a grating and a transmission type mirror. No semiconductor laser has been proposed so far.

  Accordingly, an object of the present invention is to provide a semiconductor laser having a configuration capable of suitably detecting the emission power in a semiconductor laser that provides a constant optical path using a grating and a mirror.

  Another object of the present invention is to provide a semiconductor laser capable of detecting a suitable emission power using a transmission type grating.

  Still another object of the present invention is to provide a semiconductor laser configured to detect an output power using a grating and a transmission type mirror.

  The present invention provides an oscillating means for oscillating laser light, a condensing means for condensing the laser light, and receiving the collected laser light, and emitting light of a predetermined wavelength as first-order diffracted light toward the oscillating means. A diffraction unit that reflects other light as zero-order light, a reflection unit that reflects zero-order light received from the diffraction unit, a spectroscopic unit that splits the light reflected by the reflection unit, and one of the split beams Detecting means for detecting the output power by receiving light, the diffracting means and the reflecting means are arranged so that the surface of the diffracting means and the surface of the reflecting means have a predetermined angle, and the rotation axis is diffracted The same plane as the surface of the means is arranged along a line intersecting the same plane as the surface of the reflection means, and the extending direction of the rotation axis is perpendicular to the optical axis of the laser beam from the oscillation means, and the diffraction means Arranged so as to extend parallel to the extending direction of the grating grooves of , About an axis of rotation, the the diffraction means reflecting means, by rotating while maintaining a predetermined angle, a semiconductor laser configured to adjust the wavelength of the laser beam oscillated from the oscillating means.

  The present invention provides an oscillating means for oscillating laser light, a condensing means for condensing the laser light, and receiving the collected laser light, and emitting light of a predetermined wavelength as first-order diffracted light toward the oscillating means. And a diffractive means that reflects part of the other light as zero-order light and transmits the remaining light, and a detecting means that receives the light that has passed through the diffracting means and detects the output power. Is arranged on the same plane as the surface of the diffractive means, and the extending direction of the rotation axis is perpendicular to the optical axis of the laser light from the oscillating means and extends parallel to the extending direction of the grating grooves of the diffracting means The semiconductor laser is arranged to adjust the wavelength of the laser light oscillated from the oscillation means by rotating the diffraction means about the rotation axis.

  The present invention provides an oscillating means for oscillating laser light, a condensing means for condensing the laser light, and receiving the collected laser light, and emitting light of a predetermined wavelength as first-order diffracted light toward the oscillating means. And diffracting means for reflecting other light as zero-order light, reflecting part of the zero-order light received from the diffracting means, reflecting the remaining light, and receiving and emitting the light transmitted through the reflecting means. Detecting means for detecting power, the diffractive means and the reflecting means are arranged such that the surface of the diffractive means and the surface of the reflecting means have a predetermined angle, and the rotation axis is the same as the surface of the diffractive means. The plane is arranged along a line intersecting the same plane as the surface of the reflecting means, and the extending direction of the rotation axis is perpendicular to the optical axis of the laser light from the oscillating means, and the extending direction of the grating grooves of the diffracting means Diffracting means arranged so as to extend in parallel with respect to the rotation axis Reflecting means, by rotating while maintaining a predetermined angle, a semiconductor laser configured to adjust the wavelength of the laser beam oscillated from the oscillating means.

  According to the present invention, there is provided a semiconductor laser having a configuration capable of suitably detecting an emission power in a semiconductor laser that provides a constant optical path using a grating and a mirror. Further, a semiconductor laser capable of detecting a suitable emission power even when a transmission type grating is used without using a mirror is also provided.

  Furthermore, according to the present invention, there is provided a semiconductor laser configured to detect a suitable output power when a grating and a transmission type mirror are used.

  First, the structure of the semiconductor laser according to the first embodiment of the present invention will be described with reference to FIG. The arrangement of the grating 3, the mirror 4, and the rotating shaft 7 is the same as the positional relationship of each component described with reference to FIGS. 7 and 8. Laser light from the laser diode 1 enters the grating 3 via the lens 2, and first-order diffracted light directed to the laser diode 1 and zero-order light 8 incident on the mirror 4 are output from the surface of the grating 3, The reflected light of the 0th-order light 8 is emitted from the surface 4.

  By rotating the grating 3 about the rotation axis 7, the wavelength of the oscillation light of the laser diode 1 is changed, and light can be emitted in a stable single mode. Further, at the time of the rotation, the mirror 4 is similarly rotated about the rotation axis 7, but the reflected light is maintained in a certain direction based on the principle described with reference to FIGS. 7 and 8.

  Here, the laser diode 1 corresponds to the oscillating means, the lens 2 corresponds to the condensing means, the grating 3 corresponds to the diffracting means, the mirror 4 corresponds to the reflecting means, the beam splitter 5 corresponds to the spectroscopic means, and the detector 6 corresponds to the detecting means. To do.

  In the first embodiment, the grating 3 and the mirror 4 are configured to be directly connected to each other at a predetermined angle via the rotating shaft 7. However, the grating 3 and the mirror 4 are at least at a place where light is incident. I just need it. Therefore, it is sufficient that the rotation shaft 7 is provided along a straight line that intersects the same plane as the surface of the grating 3 and the same plane as the surface of the mirror 4. The rotating shaft 7 is further arranged so that its extending direction is perpendicular to the optical path of the laser light from the laser diode 1 and is horizontal to the grating groove of the grating 3.

  In the first embodiment, in addition to the above configuration, the beam splitter 5 is arranged, the reflected light reflected from the mirror 4 is split into the transmitted light 9 and the reflected light 10, and the reflected light 10 is incident on the detector 6. The output power is detected. The reflected light 10 is preferably about 1 to 10% of the reflected light reflected from the mirror 4. This is to increase the amount of transmitted light 9 used for the original purpose. The transmitted light 9 is used for a holographic memory writer, for example.

  A lens for converging the reflected light 10 may be disposed between the beam splitter 5 and the detector 6. With such a configuration, even if the arrangement angle of the grating 3 is changed in order to change the wavelength of light oscillated from the laser diode 1, part of the laser light is always incident on the detector 6 via the beam splitter 5. .

  Next, the configuration of the second embodiment of the present invention will be described with reference to FIG. The second embodiment is a further improvement of the first embodiment. Instead of the beam splitter 5 of FIG. 1, the second embodiment uses a polarization means such as a λ / 2 wave plate 27 and a PBS (Polarizing Beam Splitter). A beam splitter) 25 is arranged.

  Laser light emitted from the laser diode 21 is incident on the grating 23 via the lens 22. Part of the incident laser light returns to the laser diode 21 from the surface of the grating 23, and the other part is reflected in the direction of the mirror 24 (reflected light 29). The reflected light 29 is further reflected by the surface of the mirror 24 and enters the PBS 25 via the λ / 2 wavelength plate 27. A part of the light incident on the PBS 25 is transmitted and emitted outward for the intended use (transmitted light 30), and the other is reflected in the direction of the detector 26 (reflected light 31).

  The grating 23 is rotated about the rotation axis 28 to adjust the wavelength of the laser light emitted from the laser diode 21. Further, from the above-described principle, the optical path of the transmitted light 30 and the reflected light 31 is kept constant by rotating the grating 23 and the mirror 24 around the rotation shaft 28 while maintaining the relative positional relationship. The rotating shaft 28 is arranged in the same manner as in the first embodiment. That is, it is only necessary to be provided along a straight line where the same plane as the surface of the grating 23 and the same plane as the surface of the mirror 24 intersect. The rotating shaft 28 is further arranged so that its extending direction is perpendicular to the optical path of the laser light from the laser diode 21 and is horizontal to the grating groove of the grating 23.

  The reflected light reflected by the mirror 24 is only S-wave laser light, but the axis of the λ / 2 wavelength plate 27 (slow axis, fast axis) is tilted with respect to the polarization direction of the laser light. To do. As a result, the laser light after passing through the λ / 2 wavelength plate 27 includes the P wave and the S wave, and a part thereof is reflected by the PBS 25. That is, the transmitted light 30 that passes through the PBS 25 and is emitted to the outside is, for example, a P wave, and the reflected light 31 that is reflected by the PBS 25 and proceeds to the detector 26 is, for example, an S wave.

  Also in the second embodiment, as in the first embodiment, it is desirable to reduce the light incident on the detector 26 as much as possible. For this purpose, the inclination of the λ / 2 wavelength plate 27 is adjusted. As in the configuration of FIG. 1, a lens for converging the reflected light 31 may be disposed between the PBS 25 and the detector 26.

  Next, the configuration of the third embodiment of the present invention will be described with reference to FIG. In this embodiment, the laser beam from the laser diode 41 is received using a grating 43 having a transmittance of 5%, for example. As a result, a small amount of transmitted light 46 is received by the detector 45, whereby the output power is detected. This transmittance may be in the range of about 1 to 10%, for example. This is to increase the amount of reflected light 47 used for the original purpose.

  When the laser light emitted from the laser diode 41 is incident on the grating 43 through the lens 42, a part of the laser light returns from the surface of the grating 43 to the laser diode 41, and the other part of the grating 43. The light is reflected from the surface and emitted toward the outside (reflected light 47), and the remaining light passes through the grating 43 and travels toward the detector 45 (transmitted light 46).

  In order to change the wavelength of the laser light emitted from the laser diode 41, the grating 43 is rotated around the rotation axis 44, and the optical path of the transmitted light 46 is slightly changed accordingly. However, in the Littrow type semiconductor laser, the variable range of such a grating arrangement angle is about 1 °, so that the transmitted light 46 is always incident on the detector 45 even if the arrangement angle of the grating 43 changes. That is not particularly difficult.

  The rotating shaft 44 is provided on the same plane as the surface of the grating 43. Further, the rotating shaft 44 is further arranged so that its extending direction is perpendicular to the optical path of the laser light from the laser diode 41 and horizontal to the grating groove of the grating 43.

  Unlike the first and second embodiments, the third embodiment does not use the above-described principle based on a combination of a grating and an additional mirror, and an additional mirror and beam splitter are arranged accordingly. There is no need to do. However, even with such a configuration, the output power can be easily detected by a single detector while adjusting the wavelength of the laser beam.

  Next, the configuration of the fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, a mirror 64 having a reflectance of 95% and a transmittance of 5% is used. This transmittance may be in the range of about 1 to 10%, for example. This is to increase the amount of reflected light 68 used for the original purpose.

  When the laser light emitted from the laser diode 61 is incident on the grating 63 through the lens 62, a part of the laser light returns from the surface of the grating 63 to the laser diode 61, and the other is reflected in the direction of the mirror 64. (Reflected light 67). 95% of the reflected light 67 is further reflected by the surface of the mirror 64 (reflected light 68), and the remaining 5% is transmitted and incident on the detector 65 (transmitted light 69).

  The rotating shaft 66 is disposed in the same manner as in the first and second embodiments. That is, it is only necessary to be provided along a straight line where the same plane as the surface of the grating 63 and the same plane as the surface of the mirror 64 intersect. The rotating shaft 66 is further arranged so that its extending direction is perpendicular to the optical path of the laser beam from the laser diode 61 and is horizontal to the grating groove of the grating 63.

  As can be seen from FIG. 8, the optical path of the reflected light 67 reflected by the grating 63 is greatly changed by the rotation of the grating 63 and the mirror 64 (about the rotation axis 66). Therefore, the optical path of the transmitted light 69 is also changed by the rotation.

  However, in an application in which the angle of the grating 63 is changed only slightly, that is, an application in which the wavelength of the laser diode 61 needs to be changed slightly, the fluctuation of the transmitted light 69 is small, and all transmitted light is transmitted by the single detector 65. 69 emission power can be detected.

  A typical example of such an application is a field related to the holographic memory described above. In holography, laser light having a specific single wavelength is used. Therefore, the inclination angle of the grating is changed in order to restore the wavelength shifted due to a temperature change or the like. For this reason, the movement amount of the inclination angle of the grating is as small as 0.1 ° or less.

  Unlike the first and second embodiments, the third embodiment does not use the above-described principle based on a combination of a grating and an additional mirror. However, the mirror 64 arranged in this manner serves to keep the laser beam emission direction constant, and also serves to divide the transmitted light 69 into the detector 65.

  Further, the transmission type mirror 64 is easier to process than the transmission type grating 43 used in the third embodiment, and in that respect, the semiconductor laser device can be configured as in the fourth embodiment. It can be said that it is relatively easy.

1 is a schematic diagram illustrating a configuration of a semiconductor laser according to a first embodiment of the present invention. It is an approximate line figure showing the composition of the semiconductor laser concerning a 2nd embodiment of this invention. It is an approximate line figure showing the composition of the semiconductor laser concerning a 3rd embodiment of this invention. It is an approximate line figure showing the composition of the semiconductor laser concerning a 4th embodiment of this invention. It is a basic diagram which shows the mechanism which adjusts the wavelength of the laser beam from a laser diode. It is a basic diagram which shows the aspect in which a laser beam injects into the group of a grating and a mirror. It is a basic diagram for demonstrating the principle in which the combination of a grating and a mirror provides the emitted light of a fixed optical path. It is a basic diagram which shows the structure of the semiconductor laser using the principle shown in FIG.

Explanation of symbols

1, 2, 41, 61 ... laser diode, 2, 22, 42, 62 ... lens, 3, 23, 43, 63 ... grating, 4, 24, 64 ... mirror, 5 ....・ Beam splitter, 25... Polarizing beam splitter, 27... Λ / 2 wave plate, 6, 26, 45, 65.

Claims (10)

An oscillation means for oscillating a laser beam;
Condensing means for condensing the laser light;
Diffractive means for receiving the condensed laser light, emitting light of a predetermined wavelength as first-order diffracted light toward the oscillating means, and reflecting other light as zero-order light;
Reflecting means for reflecting the zero-order light received from the diffraction means;
A spectroscopic means for splitting the light reflected by the reflecting means;
Detecting means for detecting the output power by receiving one of the dispersed light, and
The diffracting means and the reflecting means are arranged such that the surface of the diffracting means and the surface of the reflecting means have a predetermined angle,
The rotation axis is arranged along a line where the same plane as the surface of the diffraction means intersects the same plane as the surface of the reflection means, and the extending direction of the rotation axis is determined by the laser light from the oscillation means. Arranged so as to extend in parallel to the direction of extension of the grating grooves of the diffraction means,
A semiconductor laser characterized by adjusting the wavelength of the laser beam oscillated from the oscillation means by rotating the diffraction means and the reflection means while maintaining the predetermined angle around the rotation axis. . The semiconductor laser according to claim 1, wherein
1% to 10% of the light reflected by the reflecting means is split by the spectroscopic means and incident on the detecting means. The semiconductor laser according to claim 1, wherein
A semiconductor laser, wherein the spectroscopic means comprises a λ / 2 wavelength plate that receives light from the reflecting means, and a polarization beam splitter that receives light from the λ / 2 wavelength plate. The semiconductor laser according to claim 1, wherein
A semiconductor laser characterized in that the drive current of the oscillating means is controlled based on the emission power detected by the detecting means. An oscillation means for oscillating a laser beam;
Condensing means for condensing the laser light;
The condensed laser light is received, light having a predetermined wavelength is emitted as first-order diffracted light toward the oscillation means, a part of other light is reflected as zero-order light, and the remaining light is transmitted. Diffraction means;
Detecting means for detecting the output power by receiving the light transmitted through the diffraction means,
The rotation axis is disposed on the same plane as the surface of the diffractive means, and the extension direction of the rotation axis is perpendicular to the optical axis of the laser beam from the oscillation means, and the extension direction of the grating grooves of the diffractive means Arranged so as to extend in parallel to each other,
A semiconductor laser characterized in that the wavelength of laser light oscillated from the oscillation means is adjusted by rotating the diffraction means about the rotation axis. The semiconductor laser according to claim 5, wherein
2. A semiconductor laser according to claim 1, wherein the diffractive means has a transmittance of 1% to 10%. The semiconductor laser according to claim 5, wherein
A semiconductor laser characterized in that the drive current of the oscillating means is controlled based on the emission power detected by the detecting means. An oscillation means for oscillating a laser beam;
Condensing means for condensing the laser light;
Diffractive means for receiving the condensed laser light, emitting light of a predetermined wavelength as first-order diffracted light toward the oscillating means, and reflecting other light as zero-order light;
Reflecting means for reflecting a part of the zero-order light received from the diffraction means and transmitting the rest;
Detecting means for detecting the output power by receiving the light transmitted through the reflecting means,
The diffracting means and the reflecting means are arranged such that the surface of the diffracting means and the surface of the reflecting means have a predetermined angle,
The rotation axis is arranged along a line where the same plane as the surface of the diffraction means intersects the same plane as the surface of the reflection means, and the extending direction of the rotation axis is determined by the laser light from the oscillation means. Arranged so as to extend in parallel to the direction of extension of the grating grooves of the diffraction means,
A semiconductor laser characterized by adjusting the wavelength of the laser beam oscillated from the oscillation means by rotating the diffraction means and the reflection means while maintaining the predetermined angle around the rotation axis. . The semiconductor laser according to claim 8, wherein
2. A semiconductor laser according to claim 1, wherein said reflecting means has a transmittance of 1% to 10%. The semiconductor laser according to claim 8, wherein
A semiconductor laser characterized in that the drive current of the oscillating means is controlled based on the emission power detected by the detecting means.

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